Sighting device for firing at a moving target



Oct. 23, 1962 G. E. COEYTAUX SIGHTING DEVICE FOR FIRING AT A MOVINGTARGET Filed Oct. 22, 1956 6 Sheets-Sheet l FIGJ INVENTOR G. E. COEYTAUXOct. 23, 1962 G. E. COEYTAUX 3,059,338

SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 6Sheets-Sheet 2 m I Q $1 89, \1'

w i N N 9% m/ Q l w w k) N L m 2 INVENTOR a Georges E Coey/aaa byAlmrneys' SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22,1956 Oct. 23, 1962 G. E. COEYTAUX 6 Sheets-Sheet 3 FIG 4 INVENTOR,Georges E Coeyfaux by mm, m 14 MA Allarndys SIGHTING DEVICE FOR FIRINGAT A MOVING TARGET Filed 001.. 22, 1956 Oct. 23, 1962 G. E. COEYTAUX 6Sheets-Sheet. 4

INVENTOI? GeoigesE Coeylaux by Mum, WM

Attorneys Oct. 23, 1962 G. E. COEYTAUX 3,0

SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 I 6Sheets-Sheet 5 //V VE N TOR,

Georges E. Caeyfaux Oct. 23, 1962 cs. E. COEYTAUX 3,

SIGHTING DEVICE FOR FIRING AT A MOVING TARGET Filed Oct. 22, 1956 eSheets-Sheet s GEORGES E. COEYTA W I N VENTUR 5v MM, Mil/M ,4 TTORNE v5United rates atent @fitice Patented Got. 23, 1962 3,059,338 SIGHI'INGDEVICE FOR FWG AT A MQVENG TARGET Georges E. Coeytaux, 25 his Rue duQhateau, Neuiliy-sur-Seine, France Filed Oct. 22, 1956, Ser. No. 617,604Claims priority, application France Oct. 24, 1955 2 Claims. (6i. 33-49);

The present invention relates to a sighting device that is intended asequipment for artillery material, e.g., field artillery, self-propelledguns, guns with armored gear or recoilless guns whether or not onself-propelled guncarriages, especially for firing on moving terrestrialtargets. It is known that the function of such sighting instruments isto work out the correction or by which it is necessary to displace theline of fire of the firearm ahead of the target in order to take intoaccount the displacement of the target during the time of travel of theprojectile.

The sighting device of the invention uses the only data measurable fromthe position of firing, that is to say the tangential angular speed ofthe target and its distance. The distance is measured either with anoptical telemeter of a known type or with electromagnetic means of aknown type or is, more simply, estimated by the gunlayer. The angularspeed is, according to the invention, measured directly by the sightingdevice by the method hereinafter described. The lead angle correction onis equal to the product of the measured angular speed and the time oftravel T of the projectile. The time of travel T of the projectile is aknown linear or non-linear function of the distance. As the latter issupposed to be known, the time T is also known and it constitutes adatum in the operation of the sighting device.

According to the invention, the sighting device comprises a telescopeand means for causing to appear, in the focal field of said telescopetwo spider-lines at right angles to each other, one horizontal and theother vertical, the positions of which are controlled by a first knobfor feeding time T and by a second knob the rotation of which, whenoperated as set forth below, is consequently proportional to the producta of T by the angular speed a: of the target, and is accordinglyprovided with an a scale. There also appears a movable grating on whichthere is impressed, by means of the two knobs conjointly, a speed ofdisplacement which is equal to the angular speed of the target. Itshould be noted that, if T is a datum of the operation of the sightingdevice, a is an unknown variable until shown at knob 6, which indicatesprecisely the value desired for the correction when there has beenobtained, by means of the two knobs conjointly, the equality of thespeed of displacement of the grating and the angular speed of thetarget.

The invention will now be described in detail with reference to theaccompanying drawings, of which FIG. 1 represents the focal field of thetelescope;

FIG. 2 represents diagrammatically a sighting device according to theinvention;

FIG. 3 is a longitudinal, vertical sectional view of such a sightingdevice;

FIG. 4 is a transverse vertical section on line 4-4 of FIG. 3;

FIG. 5 is a horizontal section on line 55 of FIG. 3;

FIG. 6 is a vertical section on line 6-6 of FIG. 4; and

FIG. 7 is a perspective schematic view of the apparatus of FIGS. 3-6.

The gun-layer sees in his telescope, which is rigidly connected to thefirearm, the focal field 11 shown in FIG. 1. He sees appear in thelight, on the image of the landscape in which the target 2 is located, aluminous grating 3 of equidistant vertical lines. This grating may bedriven, with a certain lateral speed, either towards the right ortowards the left. This speed a) is, as has been seen, a function of twovariables T and u. The gun-layer, after having brought the target 2approximately into the field l of the telescope (by rotating his turretor his firearm with the aid of the sighting wheel), equalizes the speedof the target with the speed of the grating by regulating the speed ofthe grating with the aid of an operating knob 6 called the tachymetryknob the amount of rotation of which when equalization is achieved beingproportional to or, after having also regulated this speedproportionately to l/ T by rotating a knob 7, called the superelevationknob, proportionately to the superelevation H, as will be explainedlater H being supposed to be a linear function oi the time of travel T.

The tachymetry knob 5, which modulates the speed of the gratingproportionately to 0:, also displaces horizontally, in the focal planeof the telescope, a vertical spiderline 4, giving exactly the correctionon in relation to a reference line 8 and vertical numerical scales 4a.and 4b; the second or superelevation knob 7, which modulates the speedof the grating proportionately to 1/ T, displaces a horizontalspider-line 5 vertically in the focal plane of the telescope, givingexactly the superelevation H; the proper amount of rotation of knob 7 isachieved by adjusting the position of spider-line '5 relative to scales4a, 4b in accordance with the numerical value corresponding to theestimated, or known from other means, distance of the target. When thegun-layer has obtained equality of the speeds of the movable grating andof the target, the intersection a of the vertical spider-line and thehorizontal spider-line in the focal plane gives him exactly the point ofthe focal plane of his telescope with which he is to aim at the target.He then displaces his firearm and the sighting device which is fixed tothe firearm, with the sighting wheels in a direction to bring the target2 on to the crossing 9 of the two spider-lines and he then fires, orelse he waits for the movable target 2, the image of which is displacedalong the horizontal superelevation spiderline 5 to cut the verticalspider-line 4 of allowance for lateral deviation.

A non-restrictive example of embodiment of this sighting device is givenin FIG. 2.

A direct-current electric motor 10, which gives a very regular movement,drives a drum 16 on which is brightly engraved, on a dark background, ahelix 17, the image of which is projected optically into the focal planeof the telescope through the intermediary of a separating filter. Thisoptical projection is effected by any known means (collimation), so thatthe image of this helix appears in the focal plane of the telescope asequidistant vertical lines. If required, the motor may be replaced by amechanical motor with a regulator or a clockwork movement.

This motor produces the movement of the grating not directly but throughthe intermediary of two speed changers which, by way of non-restrictiveexample, may be mechanical changers with rollers or with a ball-race.These changers are of the type shown on page 25 of Computing Mechanismsand Linkages, Radiation Laboratory Series, vol. 27, McGraw-Hill BookCompany Inc., 1948. These two changers are mounted in series, onefollowing the other as shown in FIG. 2. The first changer comprises thecylinder 11, which is driven directly by the motor '10, the ball-race 12and the disc 13 and it is arranged in such a manner that the movement ofthe ballrace is connected with the movement of the knob 7 which alsoeffects the movement of the horizontal spider-line 5 of the telescope,giving the superelevation. The second changer comprises the disc 13, theball-race 14 and the cylinder 15 driving the drum 16 directly, and it isarranged in such a manner that the movement of the ballrace is connectedlinearly with the vertical spider-line 4 giving the lead-anglecorrection, these two movements being produced by the knob 6. It is seenthat, due to the fact that the distance of ball-races 12 and 14 to theaxis of the disc 13 are respectively proportional to T and the speed ofthe engraved drum 16, that is to say of the spider-lines seen clearly inthe telescope, is modulated in accordance with the ratio of the twovariables a and T, thus giving the formula which is the law oftarget-correction.

FIGS. 3, 4, 5 and 6 give a practical example of such a telescope whichhas been constructed by the applicant. The driving motor is representedat 10 (FIG. 3) and the tachymetry knob and the superelevation knob arerepresented at 6 and 7 respectively. The motor It) drives the cylinder11 by means of the tangent screw 18 and the pinion 19.

The knob 7 drives, through the intermediary of the kinematic chaincomprising the pair of pinions 20, the shaft 21, the pair of pinions 22,the oblique shaft 23 (FIG. 5) and the pair of pinions 24, thescrew-threaded rod 25 on which slides a nut which carries the ball-race12. In addition, this knob, through the intermediary of the pair ofpinions 26 (FIG. 3) and the shaft 27 having a threaded end 27a threadedinto block 33a on which glass plate 33 is mounted causes a displacementin the vertical direction of the glass plate 33 which is situated in thefocal plane of the telescope and bears the horizontal spider line 5.

The knob 6 drives, through the intermediary of the oblique shaft 30(FIG. 5) and pinions 31a in the drawings, the screw-threaded rod 31similar to the screwthreaded rod 25 and on which slides a nut whichcarries the ball-race 14. In addition, this knob effects, through thecross shaft 32, a pair of pinions, not shown, and the shaft 28, whichhas a threaded end 28athreaded into block 29a on which plate 25 ismounted, the displacement, in the horizontal direction, of the glassplate 29 which is situated in the focal plane of the telescope and bearsthe vertical spider-line 4.

The cylinder drives, through the intermediary of a kinematic chain shownin FIG. 4, the screw-threaded rod 34 which eifects the lateral movement,from right to left or from left to right, in the plane of FIG. 4, of thegrating 35. The driving arrangement for the grating is better shown inFIG. 6. This grating 35 is supported by a chassis 55 guided by the balls56 rolling in the grooves 59 (also shown in FIG. 4) and also guided bythe rod 57. The chassis 55 carries an extension 58 which forms a nutengaged with the screw 34. The rotation of the screw 34 brings about adisplacement of the grating 35 in a direction perpendicular to the planeof FIG. 6. In this embodiment, the grating 35 is a flat grating mountedon a carriage instead of being a helix carried by a cylinder as in thecase of FIG. 2. This grating is projected into the focal plane of thetelescope by the collimator 36 and the perpendicular minors 37 and 38.39 and 40 (FIG. 4) are respectively the objective and the eyepiece ofthe telescope.

In this embodiment the grating comes to a stop at the end of a certaintime. If this occurs before the gun-layer has adjusted the speed byacting upon the knob 6, the grating may be disconnected and led back toits mean position. This is done by rotation of the shaft 50 (FIG. 4)which carries for this purpose a manually engageable member, only thecross section 50a of which is shown' and which is held on shaft 50 by apin (unnumbered). The rotation of the shaft 50 rotates the plate 51,which is mounted on shaft 50, which in turn rotates, by means of thestud 52, which stud is mounted on plate 51, the

pivotal mounting 54 upon which is rotatably mounted the screw 34. Themounting 54 then turns with the shaft 60, journaled in fixed supports690, 6%, and the screw 34 is no longer engaged with the extension 58(FIG. 6) of the chassis 55. The chassis and the grating that it carriesare thus released for return to the mean position.

The system of speed-modulation by mechanical changers in cascade isgiven by way of example. It is quite obvious that the invention isequally applicable to a system of speed-modulation which carries out thelaw purely electrically or electronically.

The advantages of the invention as compared with all the proposedsystems of tachymetric telescopes giving corrections of aim are thefollowing:

(1) Absolute stability of the determination of the correction.

In fact, the grating 3 which is used for the tachymetry is independentof the spider-line used for the sighting; this obviates all the effectsof instability which are observed in tachymetric systems with singlespider-lines, in which the spider-line which is used for the sighting isthat which is also used for the tachymetry.

(2) Robustness and ease of operation.

In fact, the kinematic chain, which connects the m tOr to the rotatingcylinder 16, requires substantially no torque and needs only to be speedregulated. The displacements of the spider-lines 5 and 4, which are usedfor sighting in elevation and in direction, are carried out by the handof the gun-layer, that is to say with all the torque that is desired.The kinematic speed chain can therefore be produced with a very accuratemechanism.

The tachymetry can be carried out when the image of the target islocated at any position in the focal plane of the telescope because thegrating covers the whole of the focal field 1 and the target image 2 isstill located between two lines of the grating.

(3) The correction in direction remains marked in the telescope; this isa great advantage for any repetition of the firing.

What I claim is: 1. A gun sighting device intended to be fitted on afirearm and adapted to deliver automatically the lead correction 0:corresponding to the unknown transverse speed of a target the distanceof which is known, comprising a telescope with a first and a secondplate in its focal field, said first plate having a horizontal spiderline thereon movable vertically in said focal plane and said secondplate having a vertical spider line thereon movable horizontally in saidfocal plane, a vertical line grating movable horizontally, optical meansforming the image of said grating in the focal plane of said telescope,a first and second knob for driving said first and second platerespectively and for controlling the rate of movement of said grating, afirst plate driving means connected between said first knob and saidfirst plate for driving said horizontal spider line, a second platedriving means connected between said second knob and said Second platefor driving said vertical spider line, said first knob being adapted tointroduce the time of travel T of a bullet fired by the gun at thetarget as a function of the known distance by drivingsaid horizontalspider line, said second knob being adapted to introduce the unknownlead correction by driving said vertical spider line, and grating speedcontrol means controlled by said knobs and connected to said grating forobtaining a speed of said grating proportional to a/T, whereby theadjustment of said second knob equalizing the apparent speed of thegrating to the apparent speed of the target as seen through thetelescope maintained steady introduces the correct lead correction at.

2. A sighting device as claimed in claim 1, wherein said grating speedcontrol means comprise a first speedchanger with a drum, a plate and aball-race interposed 5 between the plate and the drum, the drum rotatingat a References Cited in the file of this patent constant speed and theposition of the ball-race in rela- UNITED STATES PATENTS tion to thecenter of the plate being proportional to the time of travel T of theprojectile, and a second speefigzggg changer with a drum, a hall-race,and the plate of the 5 2526677 Mackta 1950 first speed-changer, theposition of the last mention d u ball-race in relation to the center ofthe plate being pro- FOREIGN PATENTS portional to the correction on andthe last mentioned 579,848 Great Britain Aug. 19, 1946 drum effectingthe displacement of the grating. 63 8,828 Great Britain June 14, 1950

